Wilms tumor 1 peptide–MHC complex (WT1-MHC complex)

Wilms tumor protein 1 (WT1) is a zinc-finger transcription factor that plays a crucial role in cell growth and differentiation. While its expression is limited in healthy adult tissues (primarily podocytes and some hematopoietic stem cells), it is highly overexpressed in a wide range of hematological malignancies and solid tumors, leading to its ranking as a top priority cancer antigen by the National Cancer Institute (Cheever et al., 2009). Because WT1 is an intracellular protein, it is not accessible to conventional monoclonal antibodies; instead, it is processed by the proteasome into short peptides that are presented on the cell surface by Major Histocompatibility Complex (MHC) molecules, most commonly HLA-A*02:01 (Oka et al., 2004). These WT1 peptide–MHC complexes act as specific targets for the immune system, particularly CD8+ cytotoxic T lymphocytes. Therapeutic interventions targeting these complexes include peptide vaccines like Galinpepimut-S, TCR-engineered T-cell therapies, and TCR-mimetic antibodies that recognize the peptide-MHC interface (Dao et al., 2013). These approaches aim to provide a targeted attack against WT1-expressing malignant cells while sparing most normal tissues. Clinical development is primarily focused on treating acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), where WT1 expression is a known driver of oncogenesis.

Other names

WT1-HLA complexWilms tumor protein peptide-HLA-A*02:01 complexWT1 pMHCWilms tumor 1 antigen-MHC complex

Targeting of the peptide-MHC complex by engineered T-cell receptors (TCRs) or TCR-like antibodies to induce T-cell mediated lysis of tumor cells (Oka et al., 2004; Dao et al., 2013).